On 04/21/2014 04:26 PM, Manfred Spraul wrote: > shm_tot counts the total number of pages used by shm segments. > > If SHMALL is ULONG_MAX (or nearly ULONG_MAX), then the number > can overflow. Subsequent calls to shmctl(,SHM_INFO,) would return > wrong values for shm_tot. > > The patch adds a detection for overflows. > > Signed-off-by: Manfred Spraul <manfred@xxxxxxxxxxxxxxxx> > --- > ipc/shm.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/ipc/shm.c b/ipc/shm.c > index 382e2fb..2dfa3d6 100644 > --- a/ipc/shm.c > +++ b/ipc/shm.c > @@ -493,7 +493,8 @@ static int newseg(struct ipc_namespace *ns, struct ipc_params *params) > if (size < SHMMIN || size > ns->shm_ctlmax) > return -EINVAL; > > - if (ns->shm_tot + numpages > ns->shm_ctlall) > + if (ns->shm_tot + numpages < ns->shm_tot || > + ns->shm_tot + numpages > ns->shm_ctlall) > return -ENOSPC; > > shp = ipc_rcu_alloc(sizeof(*shp)); > Acked-by: Michael Kerrisk <mtk.manpages@xxxxxxxxx> -- Michael Kerrisk Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/ Linux/UNIX System Programming Training: http://man7.org/training/ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>